The Bureau of Prisons said Friday it is investigating the conduct of notorious former hedge fund manager Martin Shkreli after a report he was using a cellphone from the New Jersey prison where he is serving a seven-year prison term.

The Wall Street Journal reported that Shkreli was using a cellular phone to help run a pharmaceutical company, now known as Phoenixus, that he helped found. Shkreli even used the phone to attempt to fire the company’s chief executive, the Journal reported.

“When there are allegations of misconduct, they are thoroughly investigated, and appropriate action is taken if such allegations are proven true,” the bureau said in a statement. “This allegation is currently under investigation.”

Inmates found with a phone — a “greatest severity level” act — face a year in prison and a fine, the bureau said.

Shkreli’s attorney, Benjamin Brafman, declined to comment.

Shkreli, 35, went from being a rising star in the hedge fund world to Wall Street bad boy and felon. He was best known for raising by 5,000 percent the price of a drug used by some people with HIV, and smirking through interviews and congressional appearances, beefing with rappers, reporters and almost anyone else in his path. Shkreli was repeatedly banned from Twitter.

He was arrested in 2015 and sentenced last year after a federal jury found he had defrauded investors in his hedge funds, including repeatedly lying to investors about major losses.

According to the Journal, Shkreli has not wasted much time since being imprisoned. He has made friends (“Krispy” and “D-Block”), cares for prison cats and continues to wield significant power over Phoenixus, a privately held Swiss pharmaceutical company.

He estimates that the pharmaceutical company could be worth $3.7 billion by the time he is released, the Journal said.

Correction: A previous version of this report inaccurately said that the drug for which Shkreli raised the price 5,000 percent was an AIDS drug. Daraprim is used to treat toxoplasmosis infection in people with HIV.